GROWTH OF AMMONIUM OXIDIZING BACTERIA IN SOIL TREATED WITH SOME FUNGICIDES (original) (raw)
Laboratory studies were carried out to assess the effect of 50, 100 and 150ppm of three fungicides Bayleton®, Ridomil® and Labilite® on the growth of Ammonium Oxidizing bacteria (AOB) in treated soils. One kilogram (1.0kg) lots of the soil were treated with the experimental doses of the test fungicides. Another 1.0kg lot of the same soil was left untreated to serve as control. The soils thus treated were soaked by adding distilled water equivalent to 80% of the water holding capacity of the soil. The plastic pots containing the experimental soils were set on the laboratory bench under ambient conditions with regular wetting. The experimental soils were sampled after 7 days and subsequently at 7-day intervals for a period of 56 days for the quantification of AOB. One gram of the samples thus obtained was serially diluted and each dilution inoculated into the Alexander and Clarke (1965) calcium ammonium carbonate medium and incubated aerobically at 30oC for 14 days. The presence or absence of AOB in the culture tubes was determined using the Griess-Ilosvay reagents and the most probable number of AOB estimated. It was observed that application of Bayleton® at the tested doses was stimulatory to the growth of AOB; Labilite® on the other had no effect on the growth of AOB while Ridomil® was clearly inhibitory particularly when applied at a concentration of 150ppm. It was therefore concluded that the use of these fungicides on farmer’s field is both safe and even beneficial in moderate doses to the growth of AOB.
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.